lecture-19 journal bearings - NPTel - Indian Institute of Technology ...
lecture-19 journal bearings - NPTel - Indian Institute of Technology ...
lecture-19 journal bearings - NPTel - Indian Institute of Technology ...
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Machine Design II Pr<strong>of</strong>. K.Gopinath & Pr<strong>of</strong>. M.M.Mayuram<br />
With reference to Fig.2.1, an expression for viscous friction drag torque is derived<br />
by considering the entire cylindrical oil film as the “liquid block” acted upon by<br />
force F.<br />
From Newton’s law <strong>of</strong> Viscosity:<br />
<strong>Indian</strong> <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong> Madras<br />
AU<br />
F=μ h<br />
(2.1)<br />
Fig. 2.2 Laminar flow <strong>of</strong> fluid in clearance space<br />
Where F = friction torque/shaft radius = 2 T f / d<br />
A= π d l<br />
U = π d n (Where n is in rps d is in m)<br />
h = c (Where c = radial clearance = 0.5(D-d))<br />
r = d /2<br />
Substituting and solving for friction torque:<br />
2 3<br />
4 π μnlr<br />
T f �<br />
( 2.2)<br />
c
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